Answer:
     
Explanation:
For this interesting problem, we use the definition of centripetal acceleration  
       a = v² / r  
angular and linear velocity are related  
      v = w r  
we substitute  
     a = w² r 
the rectangular body rotates at an angular velocity w  
 
We locate the points, unfortunately the diagram is not shown. In this case we have the axis of rotation in a corner, called O, in one of the adjacent corners we call it A and the opposite corner A  
the distance OB = L₂  
the distance AB = L₁ 
the sides of the rectangle  
It is indicated that the acceleration in in A and B are related  
        
  
we substitute the value of the acceleration  
     w² r_A = n r_B  
the distance from the each corner is  
     r_B = L₂  
     r_A =  
  
we substitute  
    \sqrt{L_1^2 + L_2^2} = n L₂  
     L₁² + L₂² = n² L₂²  
     L₁² = (n²-1) L₂²  
 
        
             
        
        
        
Answer:
C. molecules speed up as more thermal energy is added
Explanation:
The molecules will simply speed up as more thermal energy is added to the solid. 
Thermal energy is a form of kinetic energy which is set in motion. 
- Heat causes kinetic energy build up in a body. 
- As the molecules of the solid gains heat, they will continue to increase in thermal energy. 
- They are forced to start vibrating about their fixed point. 
- Thereafter, when they have enough energy, they break free from the forces holding them. 
- Therefore, they move from a state of rest to one with a very high kinetic energy where the molecules moves rapidly. 
- This is why a solid will change to liquid and sometimes eventually gas 
 
        
             
        
        
        
Answer:
Explanation:
Capacitor of 0.75μF, charged to 70V and connect in series with 55Ω and 140 Ω to discharge. 
Energy dissipates in 55Ω resistor is given by V²/R
Since the 55ohms and 140ohms l discharge the capacitor fully, the voltage will be zero volts and this voltage will be shared by the resistor in ratio.
So for 55ohms, using voltage divider rule
V=R1/(R1+R2) ×Vt
V=55/(55+140) ×70
V=19.74Volts is across the 55ohms resistor.
Then, energy loss will be
E=V²/R
E=19.74²/55
E=7.09J 
7.09J of heat is dissipated by the 55ohms resistor
 
        
             
        
        
        
Newton's 2nd law of motion:
                       Force  =  (mass) x (acceleration)
                                   =  (1,127 kg) x (6 m/s² forward)
                                   =  (1,127 x 6)  newtons forward
                                   =    6,762 newtons forward
______________________________
             Momentum  =  (mass) x (speed)
                                 =   (69 kg) x (6 m/s)
                                 =      414 kg-m/s